Friday afternoon, the United States Environmental Protection Agency held a press conference to announce recalls for Volkswagen and its premium brand Audi over alleged TDI clean diesel cheating. The EPA says that VW and Audi used “cheat” devices in their diesel engines to fake EPA test cycles and get better emissions results than they receive on the street. The allegations are very serious and would involve the recall of over 500,000 vehicles dating from 2009 to present.

That recall could cost billions, requiring extensive retrofitting of the diesel cars the VW Group has made its name on in this country. It also represents a serious blow to the Volkswagen and Audi brands as a whole. So far, VW has not responded with anything more than a canned “we’re working closely with the EPA..” to queries from the press.

The EPA says that the TDI vehicles in question used software that detects emissions test cycles and changes the engine’s performance accordingly, resulting in lower emissions results. When a test cycle is not detected, the vehicle operates at far higher emissions to achieve higher fuel economy and performance. Emissions, say the EPA, are up to 40 times higher under normal driving.

The EPA calls the software a “defeat device” and intimates that this software is why the four-cylinder TDI engines VW and Audi use do not require extensive after-treatment systems to scrub emissions. Expensive equipment that other manufacturers often have to use with theirs, one reason that vehicles like the Chevrolet Cruze Diesel becomes cost-prohibitive compared to its gasoline counterparts and a likely reason behind Mazda not releasing a Mazda6 Diesel as promised.

Similar findings in Europe have led to investigations into Volkswagen Group diesels there as well.

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An automotive enthusiast for most of his adult life, Aaron has worked in and around the industry in many ways. He is an accredited member of the Rocky Mountain Automotive Press (RMAP), the Midwest Automotive Media Association (MAMA), and freelances as a writer and journalist around the Web and in print. You can find his portfolio at

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4 thoughts on “EPA Accuses Volkswagen Group of Cheating Diesel Emissions Tests”

  1. VW will also most likely be fined a lot of money for this emissions cheating software. Surprising they got away with this for so long.

    1. Ya, but this is the same EPA that was “cleaning up” the water and instead dumped thousands of gallons of waste into the river. So expecting them to be on top of things is like expecting TSA to actually catch a terrorist.

      1. 😀 Well the Department of Justice is probably going to do something. Don’t forgot all the class action lawsuits. Environmental lawyers are going to want to go after VW as well.

        Maximum penalty is $37,500 per car and when calculated over almost 500,000 vehicles that works out to about $18 Billion. I would hope the EPA, DoJ, Congress, or whoever fines VW the as much as possible to make an example.

        1. The 500k vehicles number is a way high estimate. It’s assuming that most VW vehicles sold with small-displacement TDI engines don’t have aftertreatment. Every one that I’ve driven did (Passat TDI, Golf TDI..).

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